Process for producing an adhesive-treated polyester fiber cord

ABSTRACT

An adhesive-treated polyester fiber cord having a high adhesion to non-vulcanized rubber, a high resistance to separation of fibers or filaments from each other, and being useful as a reinforcing cord for producing a rubber composite material such as belt having high dimensional stability and power transmission property, is produced by first impregnating a material cord a first adhesive liquid containing a polyepoxide compound and a blocked polyisocyanate compound in solid weight ratio of 1/3-1/15, by heat treating it at 160-240° C., by second treating the treated cord with a second adhesive liquid containing a resorcinol-formaldehyde resin and a rubber latex in a solid weight ratio of 1/3-1/15, by heat treating it at 180-240° C., by third treating the treated cord with a third adhesive liquid containing a resorcinol formaldehyde resin (resorcinol/formaldehyde molar ratio: 1/0.6-1/1.0) and a rubber component (including natural rubber in a content of at least 15% by weight and optionally vinyl pyridine-styrene-butadiene copolymer rubber) in a weight ratio of 1/10-1/20 and by heat treating at 140-170° C.

TECHNICAL FIELD

The present invention relates to a process for producing anadhesive-treated polyester fiber cord useful as a reinforcing cord for apower-transmission belt. More particularly, the present inventionrelates to a process for producing an adhesive-treated polyester fibercord which is suitable as a core cord of a lapped V belt and has anexcellent handling property in a belt-forming procedure, an excellentadhesion to non-vulcanized rubber used in a belt-forming procedure, anda superior bonding property to a matrix rubber after vulcanization ofthe rubber, and exhibits an excellent adhesive durability to such anextent that even when the cord is brought into contact with water vaporduring the vulcanizing procedure, the adhesive property of the cord isnot degrated, and a superior belt-forming property.

BACKGROUND ART

A polyester fiber cord generally has excellent mechanical strength,modulus of elasticity, dimensional stability and heat resistance, andthus is useful as an excellent reinforcing cord for rubber-compositematerials, for example, tires, belts and hoses which are employed undersevere conditions, and thus the use of the polyester fiber cord isexpected to increase.

Generally, the reinforcing fibers for rubber-composite materials, forexample, belts, are employed in the form of a twisted yarn cord. Theimportant properties for the cord are a high adhesive property of thecord to matrix rubber, a high mechanical strength of cord, a goodbalance between elongation under load and dry heat shrinkage of thecord, an appropriate heat shrinkage stress, and a superior adhesion ofthe cord to the non-vulcanized rubber in a forming procedure. Forexample, in the case of a belt, among the above-mentioned properties,the adhesive property and the mechanical strength of the cordsignificantly contribute to enhancing the load resistance and durabilityof the resultant belt, and the balance between the elongation under loadand the dry heat shrinkage influences the dimensional change, (forexample, the length) of the belt during movement of the belt, andclosely relates to a power transmission efficiency of the belt. Further,the adhesion of the belt to the non-vulcanized rubber in a belt-formingprocedure is a property special to the belt-forming procedure andclosely relates to peeling or separation of the cord from thenon-vulcanized rubber subjected to the belt-forming procedure anddirectly influences the yield of the product. Therefore, an adhesionprocess technology which enables the resultant product to exhibit wellbalanced properties, as mentioned above, is desired.

With respect to an adhesion of a polyester fiber cord with a rubbermatrix, various types of resorcinol-formaldehyde latex adhesives (RF_(r)adhesives) are provided by, for example, Japanese Unexamined PatentPublications No. 57-187,238 and No. 60-110,980 and Japanese ExaminedPatent Publication No. 8-2,971. When these adhesives are employed, theadhesion performance of the polyester fiber cord as a reinforcing fibercord for power transmission belt is certainly sufficient, but theadhesives are disadvantageous in that the adhesion of the cord with thenon-vulcanized rubber in the belt-forming procedure is insufficient andpeeling or separation of the cord from the rubber matrix frequentlyoccurs. Therefore, in the present stage, the close adhesion of the cordwith the non-vulcanized rubber in the belt-forming procedure is ensuredby coating a rubber adhesive prepared by dissolving an adhesive rubberin a solvent and in a small amount, on a periphery of a cord coated withan RF_(r) adhesive.

However, the above-mentioned rubber adhesive causes the workingenvironment for the belt-forming procedure to be bad and sticking of thenon-dried rubber adhesive to a worker's body is unhealthy. Also, thetreatment with the solvent-containing rubber adhesive is disadvantageousin that the waste liquid-treatment cost is high and the workingenvironment is bad, in comparison with the aqueous treatment.

DISCLOSURE OF THE INVENTION

The present invention was made, against the above-mentioned background,to provide a process for producing an adhesive-treated polyester fibercord having excellent handling property and adhesion of the cord tonon-vulcanized vulcanized rubber in a forming procedure, and a superiorbonding property of the cord with a matrix rubber, and useful for rubbercomposite materials, particularly a power-transmission belt, having ahigh durability.

The process for producing an adhesive-treated polyester fiber cord ofthe present invention comprises:

subjecting a non-twisted or twisted polyester fiber cord to a firstadhesive-treating procedure in which a first adhesive liquid comprisinga polyepoxide compound and a blocked polyisocyanate compound in a solidweight ratio of 1/3 to 1/5 is applied to the polyester fiber cord andthe first adhesive liquid-applied polyester fiber cord is heat treatedat a temperature of 160 to 240° C.;

twisting, where the polyester fiber cord has no twist, the non-twistedpolyester fiber cord;

subjecting the first adhesive-treated polyester fiber cord to a secondadhesive-treating procedure in which a second adhesive liquid comprisinga resorcinol-formaldehyde condensation product resin and a rubber latexin an effective component weight ratio of 1/3 to 1/15, is applied to thefirst adhesive-treated polyester fiber cord, and the second adhesiveliquid-applied polyester fiber cord is heat-treated at a temperature of180 to 240°C.; and

subjecting the second adhesive-treated polyester fiber cord to a thirdadhesive-treating procedure in which a third adhesive liquid comprisingan aqueous dispersion of a resorcinol-formaldehyde condensation productcomponent (RF) in a molar ratio (R/F) of resorcinol (R) to formaldehyde(F) of 1/0.6 to 1/1.0 and a rubber component (G) containing naturalrubber (NR) in a content of at least 15% by weight based on the totalweight of the rubber component (G), in a solid weight ratio (RF/G) ofthe resorcinol-formaldehyde condensation product component (RF) to therubber component (G) of 1/10 to 1/20 is applied to the secondadhesive-treated polyester fiber cord, and the third adhesiveliquid-applied polyester fiber cord is heat-treated at a temperature of140 to 170° C.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, preferably, the polyester fibers in the polyesterfiber cord are fibers treated with an epoxy compound during afiber-forming procedure.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the polyepoxide compound contained in the firstadhesive liquid is preferably selected from glycidyl ether compounds ofpolyhydric alcohol compounds.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the polyepoxide compound in the first adhesiveliquid preferably has an epoxy group content of 0.2 equivalent or moreper 100 g of the polyepoxide compound.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the blocked polyisocyanate compound is preferablyselected from addition reaction products of a polyisocyanate compoundwith a blocking agent comprising at least one member selected from oximecompounds, phenol compounds and caprolactam.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the first adhesive-treated polyester fiber cordpreferably has the first adhesive in a total solid weight of 0.5 to 1.5%by weight based on the polyester fiber cord.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the heat treatment for the first adhesiveliquid-applied polyester fiber cord is preferably carried out under astretched condition under which the first adhesive liquid-appliedpolyester fiber cord is elongated at an elongation of 2.0 to 4.5%.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the rubber latex contained in the second adhesiveliquid preferably comprises, as a main rubber component, avinylpyridine-styrene-butadiene copolymer rubber.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the second adhesive liquid optionally furthercomprises a blocked isocyanate compound in a weight ratio of 1/10 to 1/3to the solid weight of the rubber latex contained in the second adhesiveliquid.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the second adhesive-treated polyester fiber cordpreferably has the second adhesive in a total solid weight of 2.0 to3.0% based on the weight of the polyester fiber cord.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the heat treatment for the second adhesiveliquid-applied polyester fiber cord is preferably carried out under arelaxed condition under which the second adhesive liquid-appliedpolyester fiber cord is allowed to shrink at a shrinkage of 0.5 to 1.5%.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the rubber component (G) contained in the thirdadhesive liquid preferably comprises natural rubber (NR) and avinylpyridine-styrene-butadiene copolymer rubber (VpR) in a solid weightratio (NR/VpR) of 2/8 to 4/6.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the third adhesive liquid optionally furthercomprises an aqueous dispersion of carbon black (C) in an effectivecomponent weight ratio (C/(RF+G)) of the carbon black (C) to the totalof the resorcinol-formaldehyde condensation product component (RF) andthe rubber component (G) of 1/3 to 1/10.

In the process for producing an adhesive-treated polyester fiber cord ofthe present invention, the third adhesive-treated polyester fiber cordpreferably has the third adhesive in a total solid weight of 0.5 to 1.5%based on the weight of the polyester fiber cord.

BEST MODE OF CARRYING OUT THE INVENTION

The polyester fibers usable for the adhesive-treated polyester fibercord of the present invention are preferably formed from a polyesterhaving repeating units substantially consisting of ethyleneterephthalate groups. The polyester fibers usable for the presentinvention may be formed from polyesters other than the polyethyleneterephthalate, for example copolyesters of polyethylene terephthalatewith a small amount of a third component, for example, isophthalic acid,5-sodium sulfoisophthalic acid, adipic acid, tetramethylene glycol anddiethylene glycol. The polyester fibers usable for the present inventioninclude epoxy-pretreated polyester fibers prepared by treating polyesterfibers with an epoxy compound.

In the process of the present invention, a non-twisted or twistedpolyester fiber cord is subjected to the first, second and thirdadhesion procedures which will be explained in detail hereinafter. Thetwisted and non-twisted polyester fiber cord may be prepared by aconventional cord-forming method. For example, in the preparation of atwisted polyester fiber cord, a desired number of polyester fiber yarnsare set parallel to each other, the parallel yarn bundle isfirst-twisted with a desired first twist number, a desired number of thefirst-twisted yarns are set parallel to each other and subjected to afinal twisting with a desired final twist number, to form a twistedpolyester fiber cord (a material cord). The first twist number isusually smaller than the final twist number, and the twisting directionof the first twist is opposite to that of the final twist.

In the process of the present invention, the twisted or non-twistedpolyester cord (material cord) is subjected to a first adhesive-treatingprocedure with a first adhesive liquid. The first adhesive liquid forthe first adhesion procedure comprises a polyepoxide compound (E_(p))and a blocked polyisocyanate compound (I_(so)) in a solid weight ratio(E_(p)/I_(so)) of 1/3 to 1/5. The polyepoxide compound (E_(p))preferably has two or more epoxy groups per molecule. The first adhesiveliquid is in the state of an aqueous dispersion of the polyepoxidecompound (E_(p)) and the blocked polyisocyanate compound (I_(so)). Ifthe solid weight ratio (E_(p)/I_(so)) falls outside of theabove-mentioned range, the resultant adhesive-treated polyester fibercord exhibits an unsatisfactory adhesive property and an insufficientresistance to fatigue, namely durability.

The polyepoxide compound (E_(p)) usable for the first adhesion procedurepreferably has a epoxy group content of 0.2 equivalent or more per 100 gof the polyepoxide compound (E_(p)). Also, the polyepoxide compound(E_(p)) is preferably selected from polyglycidyl ether compounds ofpolyhydric aliphatic alcohol compounds, which exhibit an excellentperformance for the first adhesion procedure. The polyepoxide compoundis usually employed in the form of an aqueous solution, emulsion ordispersion. The aqueous emulsion is prepared by dissolving thepolyepoxide compound (E_(p)) in a small amount of a solvent, andemulsifying the polyepoxide compound solution in water by using aconventional emulsifying agent, for example, sodiumalkylbenzenesulfonate or sodium dioctylsulfosuccinate. When thepolyepoxide compound (E_(p)) is soluble in water, an aqueous solutionthereof is employed. The polyepoxide compound (E_(p)) may be usedtogether with a curing reaction catalyst, for example, an amine compoundor imidazol compound.

The blocked polyisocyante compound (I_(so)) for the firstadhesive-treating procedure is preferably selected from additionreaction products of a polyisocyanate compound, for example,diphenyl-methanediisocyanate or tolylenediisocyanate with a blockingagent comprising at least one member selected from oxime compounds,phenol compounds and caprolactam.

The blocked polyisocyanate compound (I_(so)) is usually in the form offine solid particles and is employed in the state of an aqueousdispersion prepared by using a dispersing agent, for example, sodiumdioctylsulfosuccinate.

The first adhesive liquid for the process of the present invention maycontain an optional component other than the polyepoxide compound(E_(p)) and the blocked polyisocyanate compound unless the optionalcomponent hinders the purpose of the present invention. However, thefirst adhesive liquid is preferably free from rubber latex.

In the first adhesive-treating procedure, the amount of the firstadhesive liquid adhered on the polyester fiber cord is preferably 0.5 to1.5%, more preferably 0.8 to 1.4%, by weight, in terms of dry solidweight, based on the weight of the polyester fiber cord. If the adhesionamount of the first adhesive liquid falls outside of the above-mentionedrange, the resultant adhesive-treated polyester fiber cord may exhibitan unsatisfactory adhesive property and a poor resistance to fatigue.

There is no limitation to the method of applying the first adhesiveliquid to the polyester fiber cord. Usually, an immersion method isapplied. The first adhesive liquid is adhered to the polyester fibercord by the immersion method and, preferably, the first adhesiveliquid-applied polyester fiber cord is dried at a temperature of 130 to160° C. for 60 to 150 seconds and then heat-treated at a temperature of160 to 240° C., more preferably 210 to 235° C. for 60 to 180 seconds,more preferably 90 to 150 seconds. The drying and heat-treatingprocedure is preferably carried out under a stretched condition underwhich the first adhesive liquid applied polyester fiber cord iselongated at an elongation of 2.0 to 4.5%, more preferably 3.0 to 4.0%,still more preferably about 3.5%, to enhance the mechanical strength ofthe cord.

When the cord has no twist, the non-twisted, first adhesive-treatedpolyester fiber cord is twisted in the similar manner to that mentionedabove.

The first adhesive-treated polyester fiber cord is subjected to a secondadhesive-treating procedure in which a second adhesive liquid comprisinga resorcinol-formaldehyde condensation product resin (RF_(r) ) and arubber latex (L) in an effective component weight ratio (RF_(r)/L) of1/3 to 1/15, preferably 1/5 to 1/12, is applied to the firstadhesive-treated polyester fiber cord, and the second adhesiveliquid-applied polyester fiber cord is heat-treated at a temperature of180 to 240°C. A mixture of the resorcinol-formaldehyde condensationproduct resin (RF_(r)) with the rubber latex (L) is referred to as anRFL adhesive, hereinafter. The RFL adhesive may be selected fromconventional RFL adhesives for rubber material treatments. Preferably,in the RFL adhesive, the molar ratio of resorcinol to formaldehyde is1/0.1 to 1/6, more preferably 1/0.5 to 1/4. When the effective componentweight ratio (RF_(r)/L) is less than 1/15, the resultant second adhesiveliquid exhibits an insufficient agglomerating force and thus anunsatisfactory adhesive performance. If the ratio (RF_(r)/L) is morethan 1/3, the resultant adhesive-treated polyester fiber cord exhibitstoo high a stiffness and an unsatisfactory mechanical strength and aninsufficient fatigue resistance.

There is no limitation to the type of the rubber latex (L). Usually,vinyl pyridine-styrene-butadiene copolymer latices are preferablyemployed as a main rubber component of the rubber latex (L). The secondadhesive liquid optionally comprises, as a cross-linking agent, ablocked polyisocyanate compound, for example, a blocking product ofdipheylmethanediisocyanate with caprolactam, in a solid weight ratio of1/10 to 1/3, more preferably about 1/5, to the solid weight of therubber latex (L). The blocked polyisocyanate compound contributes toenhancing the adhesive performance of the resultant adhesive-treatedpolyester fiber cord.

The method of applying the second adhesive liquid is not limited to aspecific method. Usually, an immersion method is employed. Preferably,the dry amount of the effective components of the second adhesive liquidapplied to the first adhesive-treated polyester fiber cord is controlledto 2.0 to 3.0% by weight, more preferably 2.2 to 2.8% by weight, basedon the weight of the polyester fiber cord.

The second adhesive liquid applied cord is preferably dried at atemperature of 150 to 180° C. for 90 to 150 seconds under such acondition that the cord is not slackened, and then heat-treated at atemperature of 180 to 240° C., more preferably 210 to 240° C. for 60 to180 seconds, more preferably 90 to 150 seconds. The heat treatment forthe second adhesive liquid-applied polyester fiber cord is preferablycarried out under a relaxed condition such that the cord is allowed toshrink at a shrinkage of 0.5 to 1.5, more preferably about 1.0%.

In an embodiment of the process of the present invention, the secondadhesive-treated polyester fiber cord is subjected to a thirdadhesive-treating procedure in which a third adhesive liquid comprisingan aqueous dispersion of a resorcinol-formaldehyde condensation productcomponent (RF) in a molar ratio (R/F) of resorcinol (R) to formaldehyde(F) of 1/0.6 to 1/1.0 and a rubber component (G) containing at leastnatural rubber (NR) in a content of at least 15% by weight based on thetotal weight of the rubber component (G), in a solid weight ratio (RF/G)of the resorcinol-formaldehyde condensation product component (RF) tothe rubber component (G) of 1/10 to 1/20, is applied to the secondadhesive-treated polyester fiber cord, and the third adhesiveliquid-applied polyester fiber cord is heat-treated at a temperature of140 to 170° C.

In third adhesive liquid, the molar ratio (R/F) of resorcinol (R) toformaldehyde (F) of the resorcinol-formaldehyde condensation productcomponent (RF) is controlled to 1/0.6 to 1/1, preferably 1/0.7 to 1/0.9,for the purpose of allowing the resultant third adhesive coating on thecord to be slightly three-dimensionally cross-linked to enhance theadhesive property of the cord itself and to improve the adhesion of theresultant cord to a non-vulcanized rubber in a product forming procedurewithout reducing the bonding property of the third adhesive coating.

For the same purpose as mentioned above, the solid weight ratio (RF/G)of the resorcinol-formaldehyde condensation product component (RF) tothe rubber component (G) is controlled to 1/10 to 1/20, preferably 1/12to 1/18. The resorcinol-formaldehyde condensation product component (RF)and the rubber component (G) are employed in the state of an aqueousdispersion. The rubber component (G) comprises at least natural rubber(NR). When an aqueous dispersion of the rubber component (G) or thenatural rubber (NR), is used, preferably, the aqueous dispersion isprepared by dispersing the rubber component in water without using adispersing agent. Even when the dispersing agent is used, the content ofthe dispersing agent is preferably restricted to less than 5% by weight,based on the dry weight of the natural rubber.

There is no limitation to the method of applying the third adhesiveliquid to the second adhesive-applied polyester fiber cord. Usually animmersion method is utilized. The amount of the effective components ofthe third adhesive liquid applied to the cord is preferably controlledto 0.5 to 1.5%, more preferably 0.8 to 1.3% by dry solid weight, basedon the dry weight of the polyester fiber cord.

In the process of the present invention, the third adhesiveliquid-applied polyester fiber cord must be heat-treated at atemperature lower than the heat treatment temperatures for the firstadhesive liquid-applied cord and the second adhesive liquid-appliedcord, namely, of 140 to 170° C., preferably 145 to 165° C., for 120 to240 seconds, preferably 150 to 200 seconds, to semi-cure the thirdadhesive coating on the cord. This heat treatment contributes toenhancing the adhesion of the resultant third adhesive coating to thenon-vulcanized rubber and to preventing the separation of the cord whenthe cord is employed to form a rubber composite product, for example, abelt. Also, the third adhesive coating exhibits excellent compatibilitywith both the second adhesive coating formed from the second adhesiveliquid and the matrix rubber used for the rubber composite product, andcan be sufficiently cross-linked and cured by the vulcanizing procedurefor the rubber composite product, for example, a belt, and thus theresultant cord can exhibit an excellent adhesive performance. Further,even when the adhesive-treated polyester fiber cord produced by theprocess of the present invention is undesirably exposed to water vapor,no reduction in adhesive performance occurs.

The third adhesive liquid optionally contains an aqueous dispersion ofcarbon black (C) produced by a conventional method, in an effectivecomponent weight ratio (C/(RF+G)) of the carbon black (C) to the totalof the resorcinol-formaldehyde condensation product component (RF) andthe rubber component (G) of 1/3 to 1/10, preferably 1/4 to 1/8. Thecarbon black (C) added to the third adhesive liquid covers theperipheral surface of the resultant adhesive-treated polyester fibercord and contributes to enhancing the resistance of the cord toultraviolet rays, and to preventing a reduction in the adhesiveperformance of the cord.

In another embodiment of the process of the present invention, the thirdadhesion procedure for the second adhesive-treated polyester fiber cordis carried out by using a third adhesive liquid comprising an aqueousdispersion of a resorcinol-formaldehyde condensation product component(RF) in a molar ratio (R/F) of resorcinol (R) to formaldehyde (F) of1/0.6 to 1/1.0 and a rubber component (G) containing natural rubber (NR)and a vinylpyridine-styrene-butadiene copolymer rubber (VpR) in a solidweight ratio (NR/VpR) of 2/8 to 4/6, in a solid weight ratio (RF/G) ofthe resorcinol-formaldehyde condensation product component (RF) to therubber component (G) of 1/10 to 1/20, and the third adhesiveliquid-applied polyester fiber cord is heat-treated at a temperature of140 to 170° C.

In the rubber component (G) for the third adhesive liquid, the naturalrubber (NR) and the vinyl pyridine-styrene-butadiene copolymer rubber(VpR) are mixed with each other in a solid weight ratio (NR/VpR) of 2/8to 4/6, preferably 3/7 to 7/13. When the ratio (NR/VpR) is more than2/8, while the adhesion of the resultant adhesive-treated cord to thenon-vulcanized rubber is enhanced, the resultant cord exhibits too higha stickiness to other cords and thus the handling property of the cordsis degraded. When the ratio (NR/VpR) is less than 4/6, the adhesion ofthe resultant cord to the non-vulcanized rubber is reduced.

In the resorcinol-formaldehyde condensation product component (RF) forthe third adhesive liquid, the molar ratio (R/F) of resorcinol (R) toformaldehyde (F) is 1/0.6 to 1/1.0, preferably 1/0.7 to 1/0.9.

The specific molar ratio (R/F) as mentioned above contributes toenabling the resultant third adhesive coating to be slightlythree-dimensionally cross-linked with the resorcinol-formaldehydecondensation product component (RF), and to enhancing the adhesiveproperty of the resultant cord so as to increase the adhesion of theresultant cord to the non-vulcanized rubber in the forming procedurewithout decreasing the bonding property of the third adhesive coating.For the same purpose as mentioned above, the solid weight ratio (RF/G)of the resorcinol-formaldehyde condensation product component (RF) tothe rubber component (G) comprising the natural rubber (N/R) and thevinyl pyridine-styrene-butadiene copolymer rubber (vpR) is controlled to1/10 to 1/20, preferably 1/12 to 1/18. The aqueous dispersion of thenatural rubber (NR) is preferably prepared by not using a surface activeagent. Even when the surface active agent is used, the content of thesurface active agent should be restricted to less than 5% by weightbased on the dry weight of the natural rubber.

There is no limitation to the method of applying the third adhesiveliquid to the second adhesive-applied polyester fiber cord. Usually animmersion method is utilized. The amount of the effective components ofthe third adhesive liquid applied to the cord is preferably controlledto 0.5 to 1.5%, more preferably 0.6 to 1.3% by dry solid weight, basedon the dry weight of the polyester fiber cord.

In the embodiment of the process of the present invention, the thirdadhesive liquid-applied polyester fiber cord must be heat-treated at atemperature lower than the heat treatment temperatures for the firstadhesive liquid-applied cord and the second adhesive liquid-appliedcord, namely, of 140 to 170° C., preferably 150 to 165° C., for 120 to240 seconds, preferably 150 to 200 seconds, to semi-cure the thirdadhesive coating on the cord. This heat treatment contributes toenhancing the adhesion of the resultant third adhesive coating to thenon-vulcanized rubber and to preventing the separation of the cord whenthe cord is employed to form a rubber composite product, for example, abelt. Also, the third adhesive coating exhibits excellent compatibilitywith both the second adhesive coating formed from the second adhesiveliquid and the matrix rubber used for the rubber composite product, andcan be sufficiently cross-linked and cured by the vulcanizing procedurefor the rubber composite product, for example, a belt, and thus theresultant cord can exhibit an excellent adhesive performance. Further,even when the adhesive-treated polyester fiber cord produced by theprocess of the present invention is undesirably exposed to water vapor,no reduction in adhesive performance occurs.

EXAMPLES

The present invention will be further illustrated by the followingexamples.

In the examples and comparative examples, the cord tensile strength,cord peeling strength from non-vulcanized rubber, and cord peelingstrength from vulcanized rubber were determined by the followingmeasurements.

(1) Tensile Strength of Cord

The tensile strength of cord was measured by using a tensile tester(model Instron 5-565, made by Instron Co.) having 4D air chucks, at acord specimen length of 250 mm at a tensile rate of 100 mm/min. Themeasurement was repeated ten times, and an average of the resultant datawas calculated. The tensile strength of the specimen was represented bythe average tensile strength.

(2) Peeling Strength Between Cord and Non-Vulcanized Rubber

Five specimens of cord were placed on a stainless steel plate base andcovered by a non-vulcanized rubber sheet having a thickness of 2 mm andfurther by a stainless steel plate. A pressure of 196 kPa (2 kgf/cm²)was applied onto the stainless steel plate surface for 10 seconds byusing a cold press, to press the rubber sheet toward the cord specimens.Then, the five cord specimens were separated from the non-vulcanizedrubber sheet at a separating rate of 200 mm/min, and the force necessaryto separate the specimens was measured and represented in units of N/5cords.

(3) Peeling Strength Between Cord and Vulcanized Rubber

A peeling strength of an adhesive-treated cord from a rubber matrix wasmeasured. Seven specimans of the cord were embedded into a surfaceportion of a non-vulcanized rubber sheet, and the cord specimen-embeddednon-vulcanized rubber sheet was vulcanized under a press pressure of4,903 kPa (50 kgf/cm²) at a temperature of 150° C. for 20 minutes. Then,two cord specimens located in both the end sides were removed, threespecimens located in both the end sides and in the center of theremaining five specimens were simultaneously peeled off from the rubbersheet at a peeling rate of 200 mm/minutes, and the force needed to peeloff the three cord specimens was measured and represented in units ofN/3 cords.

Also, a specimen of the same cord specimen-embedded, vulcanized rubbersheet as mentioned above was left in a water vapor atmosphere at atemperature of 150° C. for 60 minutes. The water vapor-exposed specimenwas subjected to the same peeling strength measurement as mentionedabove, to determine the peeling strength of the adhesive-treated cordfrom rubber matrix after exposure to water vapor.

(4) Handling Property of Cord

After the adhesive treatment for the cord was completed and theresultant adhesive-treated cord was wound around a bobbin, the cord wasunwound from the bobbin. When the efficiency of the unwinding operationwas decreased due to adhesion between the wound cord portions, thehandling property of the cord was evaluated bad and represented byclass 1. When the unwinding operation could be carried out withoutdifficulty, the handling property of the cord was evaluated good andrepresented by class 2.

Example 1

First, second and third adhesive liquids were prepared as follow.

First Adhesive Liquid

Sorbitol polyglycidyl ether (trademark: DENACOL EX-611, made by NAGASEKASEIKOGYO K.K., concentration: 100%) in an amount of 9.5 kg was mixedwith 8.5 kg of a surfactant consisting of a dialkylsulfosuccinic estersodium salt (trademark: NEOCOL SW, made by DAIICHI KOGYOSEIYAKU K.K.,concentration: 30%), and the resultant mixture was fully agitated toprepare a polyepoxide compound solution. The polyepoxide compoundsolution was mixed into 982 kg of water and the mixture was agitated ata high agitating rate, to disperse the polyepoxide compound solution inwater. Then, 76 kg of an aqueous ε-caprolactam-blockeddiphenylmethane-diisocyanate dispersion (trademark: Glylbond IL-6 (madeby EMSKEMIE CO., solid concentration: 50%) was gradually mixed with anddispersed in the aqueous polyepoxide compound dispersion. The resultantdispersion was uniformly agitated to provide a first adhesive liquid.

Second Adhesive Liquid

A resorcinol-formaldehyde primary condensation product (trademark:SUMIKANOL 700S, made by SUMITOMO KAGAKU K.K., concentration: 65%, molarratio (R/F): 1/0.6) in an amount of 19.8 kg was mixed into 154.6 kg ofwater while the mixture is agitated, then the resultant aqueous solutionwas mixed with 5.0 kg of an aqueous sodium hydroxide solution having aNaOH content of 10%, 19.9 kg of an ammonia solution having an ammoniacontent of 28%, and 16.8 kg of an aqueous formaldehyde solution having aformaldehyde content of 37%.

The aqueous mixture was gradually agitated. Then, into the aqueousmixture, 425.5 kg of a vinyl pyridine-styrene-butadiene copolymer rubberlatex (trademark: JSR0652, made by NIHON GOSEIGOMU K.K., concentration:40%) were mixed and then 92.0 kg of a blocked polyisocyante compound(trademark: DM-6011, made by MEISEI KAGAKUKOGYO K.K., concentration:33%) was added. The resultant mixture was uniformly agitated, andfinally aged in room temperature atmosphere for 24 hours. The agedmixture was employed as a second adhesive liquid.

Third Adhesive Liquid

The resorcinol-formaldehyde primary condensation product (SUMIKANOL®700S) in an amount of 5.9 kg was mixed into 800.9 kg of water whileagitating the mixture, and it was further mixed with 125.1 kg of anaqueous natural rubber dispersion prepared from a natural rubber resinliquid from which casein was removed, and which had a rubber content of60%. The mixture was fully agitated to provide a third adhesive liquid.

Preparation of Material Polyester Fiber Cord

Epoxy compound-pretreated polyester filament yarns prepared by TEIJIN,oiled with an oiling agent containing a polyglycidylether compound infilament-forming procedure and having a yarn count of 1,111 dtex/250filaments (1000 denier/250 filaments) and an intrinsic viscosity of 0.85determined in o-chlorophenol at a temperature of 20° C. were employed toprovide material polyester fiber cords.

Three epoxy compound-pretreated polyester filament yarns are setparallel with each other and the parallel yarn bundle was first twistedwith a first twist number of 15 turns/10 cm in the Z direction. Thefirst twisted yarns were set parallel with each other, and the resultantyarn bundle was final-twisted with a final twist number of 9 turns/10 cmin the S direction. A material polyester fiber cord having a thicknessof 10,000 dtex (9000 denier) was obtained. The material cord wasimpregnated with the first adhesive liquid by an immersion method usinga tire cord treatment machine (trademark: COMPUTREATER, made by CALITZLER CO.), and the first adhesive liquid-applied cord was dried at atemperature of 140° C. for 160 seconds and then heat treated at atemperature of 235° C. for 150 seconds while stretching the cord at anelongation of 3.5%. The amount of the first adhesive impregnated in thecord was 1.0% by solid weight based on the weight of the cord.

The first adhesive-treated polyester fiber cord was immersed in thesecond adhesive liquid and taken up from the liquid. The pick up of thesecond adhesive liquid applied on the first adhesive-treated cord was2.0% by dry solid weight based on the weight of the cord.

The first adhesive liquid applied cord was dried at a temperature of170° C. for 150 seconds while maintaining the cord non-elongated, andthen, the dried cord was heat treated at a temperature of 230° C. for120 second under a shrink at an shrinkage of 0.5%.

Then, the second adhesive-treated cord was immersed in the thirdadhesive liquid and taken up from the liquid. The pick up of the thirdadhesive liquid on the second adhesive-treated cord was 1.5% by drysolid weight based on the weight of the cord.

The third adhesive liquid-applied cord was dried and heat-treated at atemperature of 160° C. for 180 seconds.

A third adhesive-treated polyester cord was obtained in a prepregcondition.

The resultant adhesive-treated cord was subjected to a production of arubber composite material with natural rubber at a press-vulcanizingtemperature of 150° C. for 15 minutes under a pressure of 4,903 kPa (50kgf/cm²).

The test results are shown in Table 1.

Examples 2 to 4 and Comparative Examples 1 to 5

In each of Examples 2 to 4 and Comparative Examples 1 to 5, anadhesive-treated polyester fiber cord and a rubber composite materialcontaining the cord were produced in accordance with the same proceduresas in Example 1, except that in the first adhesive liquid, the solidweight ratio (E_(p)/I_(so)) of the polyepoxide compound (E_(p)) to theblocked polyisocyanate compound (I_(so)) was changed to as shown inTable 1; in the second adhesive liquid, the effective component weightratio (RF_(r)/L) of the resorcinol-formaldehyde condensation productresin (RF_(r)) to the rubber latex (L) was changed to as shown in Table1; and in the third adhesive liquid, the solid weight ratio (RF/G) ofthe resorcinol-formaldehyde condensation product component (RF) to therubber component (G) was changed to as shown in Table 1.

The test results are shown in Table 1.

TABLE 1 Cord Peeling Item strength Peeling strength between First SecondThird between cord and vulcanized rubber adhesive adhesive adhesive cordand Before After liquid liquid liquid Tensile non-vulcanized exposing toexposing to Ratio Ratio Ratio strength rubber water vapor water vaporExample No. (E_(p)/I_(so)) (RF_(r)/L) (RF/G) (N) (N/5 cords) (N/3 cords)(N/3 cords) Comparative 1 1/1 1/2 1/8  670 3.5 250 130 Example 2 1/2 1/51/10 675 2.8 240 120 3 1/3 1/1 1/12 680 3.0 255 115 Example 1 1/4  1/131/20 680 10.2 320 220 2 1/4 1/5 1/16 685 11.2 325 225 3 1/5 1/5 1/16 68011.6 330 210 4 1/4  1/12 1/18 675 11.2 340 215 Comparative 4 1/5  1/161/18 670 11.8 260 150 Example 5 1/6 1/5 1/21 675 12.8 270 160

Example 5

First, second and third adhesive liquids were prepared as follow.

First Adhesive Liquid

Sorbitol polyglycidyl ether (trademark: DENACOL EX-611, made by NAGASEKASEIKOGYO K.K., concentration: 100%) in an amount of 9.5 kg was mixedwith 8.5 kg of a surfactant consisting of a dialkylsulfosuccinic estersodium salt (trademark: NEOCOL SW, made by DAIICHI KOGYOSEIYAKU K.K.,concentration: 30%), and the resultant mixture was fully agitated toprepare a polyepoxide compound solution. The polyepoxide compoundsolution was mixed into 982 kg of water and the mixture was agitated ata high agitating rate, to disperse the polyepoxide compound solution inwater. Then, 76 kg of an aqueous ε-caprolactam-blockeddiphenylmethane-diisocyanate dispersion (trademark: Glylbond IL-6 (madeby EMSKEMIE CO., solid concentration: 50%) were gradually mixed with anddispersed in the aqueous polyepoxide compound dispersion. The resultantdispersion was uniformly agitated to provide a first adhesive liquid.

Second Adhesive Liquid

A resorcinol-formaldehyde primary condensation product (trademark:SUMIKANOL 700S, made by SUMITOMO KAGAKU K.K., concentration: 65%, molarratio (R/F): 1/0.6) in an amount of 19.8 kg was mixed into 154.6 kg ofwater while the mixture is agitated, then the resultant aqueous solutionwas mixed with 5.0 kg of an aqueous sodium hydroxide solution having aNaOH content of 10%, 19.9 kg of an ammonia solution having an ammoniacontent of 28%, and 16.8 kg of an aqueous formaldehyde solution having aformaldehyde content of 37%.

The aqueous mixture was gradually agitated. Then, into the aqueousmixture, 425.5 kg of a vinyl pyridine- styrene-butadiene copolymerrubber latex (trademark: JSR0652, made by NIHON GOSEIGOMU K.K.,concentration: 40% were mixed and then 92.0 kg of a blockedpolyisocyante compound (trademark: DM-6011, made by MEISEI KAGAKUKOGYOK.K., concentration: 33%) were mixed. The resultant mixture wasuniformly agitated, and finally aged in room temperature atmosphere for24 hours. The aged mixture was employed as a second adhesive liquid.

Third Adhesive Liquid

The resorcinol-formaldehyde primary condensation product (SUMIKANOL®700S) in an amount of 5.9 kg was mixed into 800.9 kg of water whileagitating the mixture, and further mixed with 37.5 kg of an aqueousnatural rubber dispersion prepared from a natural rubber resin liquidfrom which casein was removed, and having a rubber content of 60%, and131.3 kg of a vinyl pyridine-styrene- butadiene copolymer rubber latex(trademark: JSR 0652, made by NIHON GOSEIGOMU K.K., concentration: 40%).

The mixture was fully agitated and further mixed with 67.0 kg of anaqueous dispersion of carbon black (trademark: FUJICARBON 203, made byFUJI SHIKISO K.K., concentration: 28%) and 758.3 kg of water, andfurther agitated, to provide a third adhesive liquid.

Preparation of Material Cord

A material polyester fiber cord was produced by the followingprocedures.

Epoxy compound-pretreated polyester filament yarns prepared by TEIJIN,oiled with an oiling agent containing a polyglycidylether compound infilament-forming procedure and having a yarn count of 1,111 dtex/250filaments (1,000 denier/250 filaments) and an intrinsic viscosity of0.85 determined in o-chlorophenol at a temperature of 20° C. wereemployed to provide polyester fiber cords.

Three epoxy compound-pretreated polyester filament yarns are paralleledwith each other and the paralleled yarn bundle was first twisted with afirst twist number of 15 turns/10 cm in the Z direction. The firsttwisted yarns were set parallel with each other, and the resultant yarnbundle was final-twisted with a final twist number of 9 turns/10 cm inthe S direction. A material polyester fiber cord having a thickness of10,000 dtex (9000 denier) was obtained. The material cord wasimpregnated with the first adhesive liquid by an immersion method usinga tire cord treatment machine (trademark: COMPUTREATER, made by CALITZLER CO.), and the first adhesive liquid-applied cord was dried at atemperature of 130° C. for 160 seconds and then heat treated at atemperature of 235° C. for 150 seconds while stretching the cord at anelongation of 3.5%. The amount of the first adhesive impregnated in thecord was 1.0% by solid weight based on the weight of the cord.

The first adhesive-treated polyester fiber cord was immersed in thesecond adhesive liquid and taken up from the liquid. The pick up of thesecond adhesive liquid applied on the first adhesive-treated cord was2.0% by dry solid weight based on the weight of the cord.

The first adhesive liquid applied cord was dried at a temperature of170° C. for 150 seconds while maintaining the cord non-elongated and,then, the dried cord was heat treated at a temperature of 230° C. for120 second under a relaxing condition under which the cord is allowed toshrink at an shrinkage of 0.5%.

Then, the second adhesive-treated cord was immersed in the thirdadhesive liquid and taken up from the liquid. The pick up of the thirdadhesive liquid on the second adhesive-treated cord was 1.5% by drysolid weight based on the weight of the cord.

The third adhesive liquid-applied cord was dried and heat-treated at atemperature of 160° C. for 180 seconds.

A third adhesive-treated polyester cord was obtained in a prepregcondition.

The resultant adhesive-treated cord was subjected to a production of arubber composite material with natural rubber at a press-vulcanizingtemperature of 150° C. for 15 minutes under a pressure of 4,903 kPa (50kgf/cm²).

The test results are shown in Table 2.

Examples 6 to 9 and Comparative Examples 6 to 9

In each of Examples 6 to 9 and Comparative Examples 6 to 9, anadhesive-treated polyester fiber cord and a rubber composite materialcontaining the cord were produced in accordance with the same proceduresas in Example 5, except that in the first adhesive liquid, the solidweight ratio (E_(p)/I_(so)) of the polyepoxide compound (E_(p)) to theblocked polyisocyanate compound (I_(so)) was changed to that as shown inTable 2; in the second adhesive liquid, the effective component weightratio (RF_(r)/L) of the resorcinol-formaldehyde condensation productresin (RF_(r)) to the rubber latex (L) was changed to that as shown inTable 2; and in the third adhesive liquid, the solid weight ratio (RF/G)of the resorcinol-formaldehyde condensation product component (RF) tothe rubber component (G) comprising the natural rubber (NR) and thevinyl pyridine-styrene-butadiene copolymer rubber (VpR) and the weightratio (NR/VpR) of the natural rubber (NR) to the vinylpyridine-styrene-butadiene copolymer rubber (VpR) was changed to thoseas shown in Table 2.

The test results are shown in Table 2.

Example 10 and Comparative Examples 10 and 11

In each of Example 10 and Comparative Examples 10 and 11, anadhesive-treated polyester fiber cord and a rubber composite materialcontaining the cord were produced in accordance with the same proceduresas in Example 5, with the following exceptions. The materialpolyepoxide-pretreated polyester fiber cords were replaced bynon-pretreated material polyester fiber cords each prepared by such aprocedure that three polyester filament yarns having a yarn count of1,111 dtex/250 filaments (1,000 denier/250 filaments) and an intrinsicviscosity of 0.85, determined in the above-mentioned manner, were setparallel with each other, the parallel yarn bundle was first twistedwith a first twist number of 15 turns/10 cm in the Z direction, threefirst twisted yarns were set parallel with each other, and the parallelyarn bundle was final-twisted with a final twist number of 9 turns/10 cmin the S direction. The material polyester fiber cord had a thickness of10,000 dtex (9000 denier). Also, in the first adhesive liquid, the solidweight ratio (E_(p)/I_(so)) of the polyepoxide compound (E_(p)) to theblocked polyisocyanate compound (I_(so)) was changed to that as shown inTable 2; in the second adhesive liquid, the effective component weightratio (RF_(r)/L) of the resorcinol-formaldehyde condensation productresin (RF_(r)) to the rubber latex (L) was changed to that as shown inTable 2; and in the third adhesive liquid, the solid weight ratio (RF/G)of the resorcinol-formaldehyde condensation product component (RF) tothe rubber component (G) comprising the natural rubber (NR) and thevinyl pyridine-styrene-butadiene copolymer rubber (VpR) and the weightratio (NR/VpR) of the natural rubber (NR) to the vinylpyridine-styrene-butadiene copolymer rubber (VpR) was changed to thoseas shown in Table 2.

The test results are shown in Table 2.

TABLE 2 Cord Peeling Item strength Peeling strength between First Secondbetween cord and vulcanized rubber adhesive adhesive Third adhesive cordand Before After liquid liquid liquid Ratio Tensile non-vulcanizedexposing to exposing to Material Ratio Ratio Ratio Ratio strength rubberHandling water vapor water vapor Polyester Example No. (E_(p)/I_(so))(RF_(r)/L) (RF/G) (NR/VpR) (N) (N/5 cords) property (N/3 cords) (N/3cords) fiber cord Comparative  6 1/1 1/2 1/8  3/7 670 3.5 2 220 10Polyepoxide- Example  7 1/3 1/5 1/12 1/9 680 3.0 2 225 85 pretreatedExample  5 1/4  1/13 1/20 3/7 680 5.2 2 320 220  6 1/3 1/5 1/12 8/2 6758.8 1 310 210  7 1/4 1/5 1/16 3/7 685 5.8 2 325 245  8 1/5 1/5 1/16 4/6670 6.6 2 310 220  9 1/4  1/12 1/18 3/7 675 6.2 2 320 230 Comparative  81/5  1/16 1/18 3/7 670 5.8 2 260 50 Example  9 1/6 1/5 1/21 10/0  66510.8 1 170 40 Example 10 1/4 1/5 1/16 3/7 682 5.6 2 316 218Non-pretreated Comparative 10 1/4 1/5 1/16  0/10 683 2.5 2 315 90Example 11 1/1 1/5 1/16 3/7 680 5.2 2 260 168

INDUSTRIAL APPLICABILITY

The process of the present invention enables an adhesive-treatedpolyester fiber cord, having excellent mechanical properties and a highresistance to separation of the fibers or filaments, in the cord, fromeach other in a rubber composite material-forming procedure, whichseparation resistance contributes to enhancing the production efficiencyof the rubber composite material, an excellent bonding property to amatrix rubber of the rubber composite material, to be produced. Also,the adhesive-treated polyester fiber cord produced by the process of thepresent invention is useful as a reinforcing cord for rubber compositematerials, for example, belts, having a high dimensional stability, anexcellent power-transmission property and a superior resistance tofatigue.

What is claimed is:
 1. A process for producing an adhesive-treatedpolyester fiber cord comprising: subjecting a non-twisted or twistedpolyester fiber cord to a first adhesive-treating procedure in which afirst adhesive liquid comprising a polyepoxide compound and a blockedpolyisocyanate compound in a solid weight ratio of 1/3 to 1/5 is appliedto the polyester fiber cord and the first adhesive liquid-appliedpolyester fiber cord is heat treated at a temperature of 160 to 240° C.;twisting, where the polyester fiber cord has no twist, the non-twistedpolyester fiber cord; subjecting the first adhesive-treated polyesterfiber cord to a second adhesive-treating procedure in which a secondadhesive liquid comprising a resorcinol-formaldehyde condensationproduct resin and a rubber latex in an effective component weight ratioof 1/3 to 1/15, is applied to the first adhesive-treated polyester fibercord, and the second adhesive liquid-applied polyester fiber cord isheat-treated at a temperature of 180 to 240° C.; and subjecting thesecond adhesive-treated polyester fiber cord to a thirdadhesive-treating procedure in which a third adhesive liquid comprisingan aqueous dispersion of a resorcinol-formaldehyde condensation productcomponent (RF) in a molar ratio (R/F) of resorcinol (R) to formaldehyde(F) of 1/0.6 to 1/1.0 and a rubber component (G) containing naturalrubber (NR) in a content of at least 15% by weight based on the totalweight of the rubber component (G), in a solid weight ratio (RF/G) ofthe resorcinol-formaldehyde condensation product component (RF) to therubber component (G) of 1/10 to 1/20, is applied to the secondadhesive-treated polyester fiber cord, and the third adhesiveliquid-applied polyester fiber cord is heat-treated at a temperature of140 to 170° C.
 2. The process for producing an adhesive-treatedpolyester fiber cord as claimed in claim 1, wherein the polyester fibersin the polyester fiber cord are fibers treated with an epoxy compoundduring a fiber-forming procedure.
 3. The process for producing anadhesive-treated polyester fiber cord as claimed in claim 1, wherein thepolyepoxide compound contained in the first adhesive liquid is selectedfrom glycidyl ether compounds of polyhydric alcohol compounds.
 4. Theprocess for producing an adhesive-treated polyester fiber cord asclaimed in claim 1, wherein the polyepoxide compound in the firstadhesive liquid has a epoxy group content of 0.2 equivalent or more per100 g of the polyepoxide compound.
 5. The process for producing anadhesive-treated polyester fiber cord as claimed in claim 1, wherein theblocked polyisocyanate compound is selected from addition reactionproducts of a polyisocyanate compound with a blocking agent comprisingat least one member selected from oxime compounds, phenol compounds andcaprolactam.
 6. The process for producing an adhesive-treated polyesterfiber cord as claimed in any of claim 1 and 3 to 5, wherein the firstadhesive-treated polyester fiber cord has the first adhesive in a totalsolid weight of 0.5 to 1.5% by weight based on the polyester fiber cord.7. The process for producing an adhesive-treated polyester fiber cord asclaimed in claim 1, wherein the heat treatment for the first adhesiveliquid-applied polyester polyester fiber cord is carried out under astretched condition under which the first adhesive liquid-appliedpolyester fiber cord is elongated at an elongation of 2.0 to 4.5%. 8.The process for producing an adhesive-treated polyester fiber cord asclaimed in claim 1, wherein the rubber latex contained in the secondadhesive liquid comprises, as a main rubber component, avinylpyridine-styrene-butadiene copolymer rubber.
 9. The process forproducing an adhesive-treated polyester fiber cord as claimed in claim1, wherein the second adhesive liquid further comprises a blockedisocyanate compound in a weight ratio of 1/10 to 1/3 to the solid weightof the rubber latex contained in the second adhesive liquid.
 10. Theprocess for producing an adhesive-treated polyester fiber cord asclaimed in any of claim 1, 8 and 9, wherein the second adhesive-treatedpolyester fiber cord has the second adhesive in a total solid weight of2.0 to 3.0% based on the weight of the polyester fiber cord.
 11. Theprocess for producing an adhesive-treated polyester fiber cord asclaimed in claim 1, wherein the heat treatment for the second adhesiveliquid-applied polyester fiber cord is carried out under a relaxedcondition under which the second adhesive liquid-applied polyester fibercord is allowed to shrink at a shrinkage of 0.5 to 1.5%.
 12. The processfor producing an adhesive-treated polyester fiber cord as claimed inclaim 1, wherein the rubber component (G) contained in the thirdadhesive liquid comprises natural rubber (NR) and avinylpyridine-styrene-butadiene copolymer rubber (VpR) in a solid weightratio (NR/VpR) of 2/8 to 4/6.
 13. The process for producing anadhesive-treated polyester fiber cord as claimed in claim 1, wherein thethird adhesive liquid further comprises an aqueous dispersion of carbonblack (C) in an effective component weight ratio (C/(RF+G)) of thecarbon black to the total of the resorcinol-formaldehyde condensationproduct component (RF) and the rubber component (G) of 1/3 to 1/10. 14.The process for producing an adhesive-treated polyester fiber cord asclaimed in any of claims 1, 12 and 13, wherein the thirdadhesive-treated polyester fiber cord has the third adhesive in a totalsolid weight of 0.5 to 1.5% based on the weight of the polyester fibercord.